They travelled to the Beijing Olympics and to the World Cup in Germany, to New Zealand for the rugby and most recently to Ukraine and Poland for Euro 2012. When the London Games open in just over a month's time, one of the UK's most successful exports, the ticket tout, will be coming home.

Of all the countries in the world it seems Britain produces the most ticket touts, according to police. Some are in it because their parents were, and families who have been in the business for generations perceive it as nothing more than a twist on being a market trader.

Others represent a link in the chain of organised crime gangs, which have added the illegal market in high-profile sports and music tickets to their criminal portfolio.

One alleged tout investigated by the Metropolitan police was suspected of luring people via social networking sites to a fraudulent website offering Olympic tickets. He faces trial.

Another, Anthony O'Mahony, 47, from Hertfordshire, was fined £52,000 for ticket touting in February and subjected to a £70,000 confiscation order. O'Mahony, who said he was a ticket agent, was believed by police to have earned up to £543,000 from his activities.

When police raided O'Mahony's office in Camden, north London, they discovered multiple membership cards for two football clubs. O'Mahony used other people's identities to apply for the memberships, which he used to buy tickets that he had sent to a rented postal box in central London.

He then sold the tickets online at inflated prices. Police said £18,000 of his profits was laundered through property in Spain.